Gas valves for controlling gas flow in appliances are well known. Further, variable flow gas valves that permit variable flows are known. Variable flow gas valves allow a user to adjust the flow of gas to adjust the temperature of a connected burner. For example, in an oven or a range, cooks routinely adjust the cooking temperature of the appliance depending on the object being cooked or the desired method of cooking. The cook adjusts the desired cooking temperature by operably adjusting the flow of gas allowed to the burner by operably adjusting the variable flow gas valve. Typically, this is done by turning a knob or adjusting a temperature setting for an electronic control system for the gas valve to signal the desired cooking temperature.
Numerous gas valve arrangements and methods of controlling the gas valve arrangements to adjust gas flow through the gas valve have been used in the past. Some gas valves use discrete settings that provide finite incremental adjustments to the gas flow depending on the configuration of the gas valve.
One particular example of this valve arrangement is illustrated in U.S. patent application Ser. No. 11/507,107 entitled “Variable Flow Valve,” filed Aug. 21, 2006, and having U.S. Pat. Publ. No. 2006/0278285, the teachings and disclosures of which are incorporated by reference herein in their entirety. This valve is adjustable between a few finite positions such that the valve will provide a discrete number of flow rates therethrough and coincidentally a discrete number of cooking temperatures for a corresponding attached burner. The valve includes a plurality of solenoids that drive the valve member to a plurality of different positions. The discrete flow rates are provided by aggregating the number of open apertures in the valve member or selecting apertures in the valve that have progressively larger openings. However, because the valve only has discrete positions, the prior art valve does not have infinite adjustability between the discrete positions and their corresponding flow rates.
Other gas valves attempt to provide for more infinite adjustability by providing a tapered valve member that inter-acts with a cooperating valve seat. The valve adjusts the flow rate therethrough by moving the tapered valve member toward and away from the valve seat. When the valve member moves towards the valve seat, the opening therebetween becomes smaller restricting flow and reducing the flow rate. Similarly, when the valve member moves away from the valve seat, the opening therebetween becomes larger allowing for increased flow therethrough. Thus, flow rates can be infinitely adjusted between maximum and minimum flow rates by infinitely adjusting the position of the valve member between a maximum flow rate position and a minimum flow rate position. However, as there has been a move toward electronic control of gas valves using solenoid drive devices, providing for this infinite adjustment has been difficult if not impossible because solenoids typically provide discrete amounts of movement.
Some valves have utilized a solenoid to drive the valve member against a biasing means, typically a spring, and have adjusted the amount of current through the solenoid to adjust the force the valve member applies against the spring to adjust the position of the valve member.
The present invention relates to improvements over the current state of the gas valve art.